Anatomy. Introduction to A & P. Complementarity. Physiology ORGANIZATIONAL LEVELS

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1 Anatomy Introduction to A & P Anatomy and Physiology Text and Laboratory Workbook, Stephen G. Davenport, Copyright 2006, All Rights Reserved, no part of this publication can be used for any commercial purpose. Permission requests should be addressed to Stephen Davenport, Link Publishing, P.O. Box 15562, San Antonio, TX, Anatomy is the study of structure and structural relationships of the body and / or its parts. Anatomy includes many different divisions such as: Cellular anatomy Developmental anatomy Gross anatomy Histological anatomy Microscopic anatomy Regional anatomy Systemic anatomy Surface anatomy Physiology Physiology is the study function of the living body and/or its parts. Physiology includes many divisions such as: Cell physiology Pathology Systemic physiology Special (organ) physiology Complementarity Complementarity refers to the interrelationship of structure (anatomy) and function (physiology). Complementarity is seen in all aspects of human anatomy and physiology and is important in understanding how the body or a structure works in a particular way. ORGANIZATIONAL LEVELS (1) Chemical level of organization The chemical level is the lowest level of organization. Atoms and molecules and their chemical interactions play an essential role in the structural and functional aspects of the cell. (2) Cellular level of organization Cells are dependent upon the structural and functional aspects of their chemistry and are the building blocks of tissues. According to the cell theory, all living things are made of cells, cells are the basic units of life, and cells come only from preexisting cells. (3) Tissue level of organization Tissues are groups of similar cells united to perform a particular function and are the building blocks of organs. There are four fundamental groups of tissues: epithelial tissue, connective tissue, muscular tissue, and neural tissue. (4) Organ level of organization Organs are formed from the organization of several tissues that enable it to perform a particular function. Organs are the building blocks of systems. 1

2 (5) Organ system level of organization Organ systems are formed from the interaction of associated organs. Systems are the building blocks of the organism. There are eleven systems of the body that work together to form the structural and functional components of the organism, the individual. (6) Organism level The organism is the highest level of organism and is organized from the following eleven organ systems. Figure 1.1 Systems of the body There are eleven structural systems of the body and one function system (immunity). Cardiovascular system Heart, blood vessels, and blood. Transport of blood; including cells, nutrients, wastes, gases, hormones, etc. Digestive system Digestive tract which includes mouth, esophagus, stomach, small intestine, large intestine, anus, and accessory organs such as salivary gland, pancreas, liver and gallbladder Processing and absorption of nutrients Endocrine system Organs which produce hormones (chemical messengers) which include pituitary, thyroid, thymus, testes, ovaries, etc. Long-term regulation of systems by production and release of hormone Integumentary system Includes the skin, hair, nails, sweat glands and oil glands Protection (by skin, hair, etc.), site of sensory receptors, involved in body temperature control, etc. Lymphatic system Includes lymph nodes, lymphatic vessels and their fluid called lymph, tonsils, spleen, and thymus Production of lymphocytes for immunity, and collects, filters, and transports fluid (lymph) Muscular system Includes the skeletal muscles Movement of the body and involved in body temperature regulation Nervous system Includes the brain, spinal cord, nerves, and receptors Immediate control of systems, personality, emotions, etc. Reproductive system Male: Includes testes, ductus (vas) deferens, prostate, seminal vesicles, penis. Female: Includes ovaries, fallopian tubes, uterus, and vagina. Production of gametes (sperm, egg), implantation and development Respiratory system Includes the nasal cavity, voice box (larynx), windpipe (trachea), and lungs Delivery of air to lungs for oxygen and carbon dioxide exchange Skeletal system Bones which form the skeleton Includes the skeleton which supports, protects, provides for storage of calcium, and serves as a site of blood cell production Urinary system Includes the kidneys, ureters, urinary bladder, and urethra Includes the production, storage, and elimination of urine, which involves regulation of water, electrolytes, and blood ph. 2

3 CHARACTERISTICS OF HUMAN LIFE Among the characteristics of the living human body are the following six processes: metabolism responsiveness growth movement differentiation reproduction Metabolism Metabolism is generally defined as the sum of all the physical and chemical processes that pertain to the body's chemistry. Catabolism Catabolism is the destructive phase of metabolism. Catabolism involves the breakdown of large substances into smaller units. Anabolism Anabolism is the constructive phase of metabolism. Usually, we think of anabolism as the process of building molecules from smaller units derived from the catabolism of nutrients. Growth Three examples of growth: Increase in the number of cells Growth characterized by an increase in the number of cells is by the process of cell division. Increase in the size of the cells Growth characterized by an increase in the size of cells is by cellular anabolic processes such as the manufacture and storage of lipids (triglycerides) in adipose (fat) cells. Increase in the amount extracellular material Growth characterized by an increase in the amount of substance outside of cells (extracellular materials) is seen in many tissues such as bone, tendons, etc. Differentiation Differentiation is the process where cells acquire an individual identity that results from progressive diversification. Responsiveness Responsiveness is the ability to react and depends upon irritability, a response to a stimulus. Stimulus Any aspect of our internal and external environments can be perceived as a stimulus if it causes a functional reaction in a receptor. Receptors are cells (or groups of cells) that respond to stimuli and are associated with the nervous and the endocrine systems. Thus, the effect of the change is usually a neural and / or hormonal response. Movement To respond to the environment and to maintain local conditions, motion begins with controlled molecular actions within the cell. These interactions determine (1) movements within the cell, (2) movement of the cell itself, or the movements of (3) a tissue, (4) an organ, or (5) the body. Reproduction The ability of cells to give rise to offspring is essential for life. Two processes involved in cell reproduction are mitosis and meiosis. Mitosis is a process of cell division that produces daughter cells that are identical genetic copies. Meiosis is a process of cell division that reduces a cell's chromosome number to one-half (one chromosome from each chromosome pair) so that the resulting cells function as gametes. Ova contain the maternal (female) and sperm contain the fraternal (male) chromosome sets. Cell reproduction (1) provides for growth (2) maintains a cell population (3) maintains the survival of the organism HOMEOSTASIS Homeostasis is the dynamic maintenance of stability in the internal environment of the body. Homeostasis involves multiple systems to keep the body within equilibrium. Control mechanisms Each system exerts its own control mechanisms to keep its attributes within normal limits. There are three basic components to a control mechanism: 1. Receptors Receptors are the components that respond to a change (a stimulus) in the environment. 2. Control center A control center analyzes information, compares this information for compatibility with its normal range, and if necessary mediates a response by an effector to make adjustments to maintain the system within its normal limits. 3. Effector Effectors, which include muscles and glands, are regulated by the control center to make adjustments, or responses, to maintain normal limits. This "new" information is monitored (receptors) and "fed-back" to the control center. Thus, homeostasis involves "feedback" mechanisms that continually monitor and adjust body systems. The two feedback mechanisms are called negative feedback and positive feedback. Negative Feedback Mechanisms Negative feedback mechanisms are most common and serve to keep the body's systems within normal ranges. Negative feedback mechanisms are control mechanisms which produce a response that is opposite (negative) to that of the change (stimulus). Thus, these mechanisms keep a system within normal limits by reversing (negating) changes. 3

4 Positive Feedback Mechanisms Positive feedback mechanisms are few in number and promote homeostasis by producing a response that is in the same direction (positive) as the stimulus. Common examples of positive feedback mechanisms (loops or cascades) include responses such as blood clotting (platelet aggregation) and childbirth. Figure 1.2 Figure 1.3 ORGANIZATION AND TERMINOLOGY Positions Anatomical position Anatomical position is the standard reference position of the body. the person is standing erect and facing forward, the feet are slightly apart and pointing forward, the arms are hanging down at the sides with the palms facing forward. Figure 1.4 REGIONAL TERMINOLOGY Supine position Supine position is a position where the person is lying with the face upward, or lying on the back surface of the body. Prone position Prone position is a position where the person is lying with the face downward, or lying on the front surface of the body. The body is divided into two major regions, the axial and appendicular regions. Figure 1.5 4

5 Definition of terms are in workbook Figure 1.6 Definition of terms are in workbook Figure 1.7 DIRECTIONAL TERMINOLOGY Directional terminology is used to describe the location of structures in relationship to each other. This description uses the anatomical position of the body as the frame of reference with the location of the organs (or their structures) referenced to in directional/location relationships. Superior is commonly used to refer to: the upper surface of an organ or structure a location at a higher level an upward direction Superior Figure 1.8 Inferior is commonly used to refer to: the lower surface of an organ or structure a location at a lower level a downward direction Inferior Anterior is commonly used to refer to: the front (or ventral) surface of the body a location at the front of a structure a location in the front of a structure affecting the front of a structure a direction toward the front of a structure Anterior Figure 1.9 Figure

6 Posterior Medial Posterior is commonly used to refer to: the back (or dorsal) surface of the body a location at the back of a structure a location in the back of a structure affecting the back of a structure a direction toward the back of a structure Medial is commonly used to refer to: a location at the mid-line direction toward the mid-line Figure 1.11 Figure 1.12 Lateral is commonly used to refer to: a location away from the mid-line direction away from the mid-line Lateral Intermediate is commonly used to refer to: a location between two structures Intermediate Figure 1.14 Figure 1.13 Proximal Distal Proximal is commonly used to refer to a location closer to the point of attachment of the appendage, or limb closer to the origin of the structure Figure 1.15 Figure 1.16 Distal is commonly used to refer to a location farther from the attachment of the appendage, or limb farther from the origin of the structure Figure 1.17 Figure

7 Superficial refers to a location toward or at the surface of the body surface of a structure Superficial Deep refers to a location away from or at the surface of the body surface of a structure. Deep Figure 1.19 Figure 1.20 BODY PLANES AND SECTIONS Frontal plane The body and its structures are often studied along planes, flat two dimensional surfaces that are produced by connecting three points of reference, or by their corresponding sections, actual cuts. Dissections require actual cuts (sections) that follow planes. Figure 1.21 Frontal plane (coronal is a commonly used synonym) A frontal plane is a vertical plane that divides the body, or a structure, into anterior and posterior portions. Sagittal planes are anteroposterior planes that divides the body, or a structure, into right and left portions. Sagittal Planes Midsagittal (median) Plane A midsagittal (median) plane is a midline sagittal plane that divides the body, or a structure, into equal right and left halves. Figure 1.22 Figure

8 Parasagittal Plane A parasagittal plane is a sagittal plane that does not divide the body, or a structure, into equal right and left halves. Figure 1.24 The Visible Human Project Special Announcement The Fourth Visible Human Project Conference Sponsored by the University of Colorado Center for Human Simulation Location: Keystone Resort, Keystone, Colorado October 17-19, 2002 Further Information Overview The Visible Human Project is an outgrowth of the NLM's 1986 Long-Range Plan. It is the creation of complete, anatomically detailed, three-dimensional representations of the normal male and female human bodies. Acquisition of transverse CT, MR and cryosection images of representative male and female cadavers has been completed. The male was sectioned at one millimeter intervals, the female at one-third of a millimeter intervals. The long-term goal of the Visible Human Project is to produce a system of knowledge structures that will transparently link visual knowledge forms to symbolic knowledge formats such as the names of body parts. Sagittal Views Female Head Virtual Corpse Female Body Frontal Plane Male Head A frontal plane is a vertical plane that divides the body, or a structure, into anterior and posterior portions. Male Body Figure

9 Transverse Plane A transverse plane is a horizontal plane (at a right angle to a vertical plane) that divides the body, or a structure, into superior and inferior portions Female body Female head Figure 1.26 Male body Male head BODY CAVITIES AND THEIR MEMBRANES Spaces within the body may be classified as cavities. There are several types of body cavities and covering membranes. The two largest body cavities, the (1) dorsal body cavity and (2) ventral body cavity, are presented in this study. Figure 1.27 Dorsal Body Cavity Ventral Body Cavity The dorsal body cavity is the cavity located at the dorsal, or posterior, portion of the body. Cranial cavity The cranial cavity is the superior portion of the dorsal body cavity. It is formed by the bones (crainial bones) surrounding cranial cavity, which contains the brain and associated structures. Vertebral cavity The vertebral cavity is the inferior portion of the dorsal body cavity. It is formed by the vertebral canal of the vertebrae and contains the spinal cord and associated structures. Figure 1.28 The ventral body cavity is the cavity located near the ventral, or anterior, portion of the body. It is divided as follows: Thoracic cavity A. Right and left lungs each invested with serous membrane with associated pleural cavities B. Heart invested with serous membrane. The outer serous membrane lines the pericardial sac, the outer wall of the pericardial cavity. C. Mediastinum the middle region of the thorax and contains all thoracic organs (viscera) except lungs Abdomino-pelvic cavity A. Abdominal cavity B. Pelvic cavity Figure

10 Thoracic Cavity The thoracic cavity is the superior portion of the ventral body cavity. The diaphragm forms its floor. The thoracic cavity contains the lungs and the mediastinum. Diaphragm The muscular diaphragm forms the floor of the thoracic cavity and the roof of the abdomino-pelvic cavity. Mediastinum The mediastinum is the medial region of the thorax and contains all of the thoracic viscera (internal organs) except the lungs (contents include: the heart and its pericardium, trachea, esophagus, major blood vessels, etc.) Figure 1.31 Figure 1.30 LUNGS; Membranes and Cavities Pleura Pleural cavities The two pleural cavities are subdivisions of the thoracic cavity and each surround a lung. A pleural cavity is a potential space formed by a single serous membrane arranged so that it has both outer and inner boundaries. fluid. Figure 1.32 Pleura The pleura is a delicate serous membrane that lines each half of the thorax and covers the surface of each lung of the same side. Parietal pleura The parietal pleura is the portion of the serous membrane that lines the outer wall (thoracic wall) of the pleural cavity. Pulmonary (visceral) pleura The pulmonary pleura is the portion of the serous membrane that forms the inner wall of each pleural cavity and lines each lung. Laboratory Animal Demonstration Figure 1.33 Observe the laboratory animal on demonstration for identification of the following: thorax diaphragm thoracic cavity parietal pleura lungs pleural cavity mediastinum pulmonary pleura Figure

11 HEART; Membranes and Cavity Pericardium Pericardial cavity The pericardial cavity is a potential space surrounding the heart formed between the two serous membranes, the (1) parietal pericardium and the (2) visceral pericardium. It contains a microscopic film of friction-reducing serous fluid called pericardial fluid. Figure 1.35 Pericardium The pericardium is a membrane which can be described as consisting of two parts, the fibrous pericardium and the serous pericardium. Parietal pericardium The parietal pericardium is the portion of the serous membrane that forms the inner lining of the fibrous pericardium. The parietal and the fibrous pericardia make the pericardial sac. Visceral pericardium The visceral pericardium is the portion of the serous membrane that forms the inner wall of the pericardial cavity by covering the heart. The visceral pericardium is also called the epicardium. Figure 1.36 Figure 1.37 ABDOMINO-PELVIC CAVITY Abdomino-pelvic cavity The abdomino-pelvic cavity is the inferior portion of the ventral body cavity. It is divided into the (1) abdominal and (2) pelvic cavities. A line that connects the superior portions of the sacrum and the pubic bones divides the superior abdominal cavity from the inferior pelvic cavity. Figure 1.38 ABDOMINO-PELVIC CAVITY Abdominal cavity The abdominal cavity is the superior portion of the abdomino-pelvic cavity. Pelvic cavity The pelvic cavity is the inferior portion of the abdomino-pelvic cavity. Peritoneum The peritoneum is the serous membrane that lines the abdomino-pelvic cavity and folds inward over most of the abdominal and pelvic viscera. 11

12 Peritoneal cavity Peritoneal cavity The peritoneal cavity is a potential space formed by the two portions of the peritoneum, the (1) parietal peritoneum and the (2) visceral peritoneum. It surrounds most of the viscera of the abdomino-pelvic cavity and contains a microscopic film of serous fluid. Some organs (or portions of) are not located within the peritoneal cavity and are called retroperitoneal (kidneys are an example). Figure 1.38 Peritoneum Parietal peritoneum The parietal peritoneum is the portion of the serous membrane that lines the outer wall (abdomino-pelvic wall) of the peritoneal cavity. Visceral peritoneum The visceral peritoneum is the portion of the serous membrane that lines the inner wall of the peritoneal cavity. The visceral peritoneum covers of most of the viscera of the abdominopelvic cavity. Laboratory Animal Demonstration Observe the laboratory animal on demonstration for identification of the following: abdominal cavity liver visceral peritoneum stomach peritoneal cavity small intestine parietal peritoneum spleen diaphragm Figure 1.39 Figure 1.40 ABDOMINO-PELVIC REGIONS The description of the location of organs within the abdomino-pelvic cavity is simplified by dividing the cavity into nine regions. The regions are described by drawing four lines on the surface of the body that follow two transverse (horizontal) planes and two sagittal planes. Figure 1.41 Figure

13 ABDOMINO-PELVIC QUADRANTS The description of the location of organs within the abdomino-pelvic cavity is further simplified by dividing the cavity into quadrants. The quadrants are described by drawing lines on the surface of the body that follow a transverse (horizontal) plane, and a midsagittal (median) plane that intersect at the umbilicus. Figure 1.43 IMAGING Several imaging techniques are used in anatomical studies and medicine. These include: radiographs, or X-rays, sonography, or ultrasound (US) computerized tomography, (CT), also called computerized axial tomography, (CAT) magnetic resonance imaging (MRI) positron emissions tomography, (PET) Radiography, or x-ray Ultrasound (US) imaging X-ray films are produced by exposing x-ray sensitive film to a beam of electromagnetic energy (xrays). As the x-rays pass through a medium, which contains regions of different densities, each region absorbs (or transmits) the electromagnetic energy depending upon its density. Thus, the exposure of the film depends upon how much of the electromagnetic energy is absorbed (or transmitted). Ultra sound (US) imaging is also referred to as ultrasound scanning or sonography. Images are produced by projecting a beam of highfrequency sound waves into the body and analyzing the waves that are reflected back. The images seen on the monitor are real-time images, which may be electronically stored or printed. Figure 1.45 Figure 1.44 Computerized Tomography (CT) Magnetic Resonance Imaging (MRI) Computerized tomography uses electromagnetic energy (x-rays) projected in a 360-degree motion around the body to image the body in horizontal planes. A computer is used to manipulate the multiple recordings to produce a detailed image. Figure 1.46 Magnetic resonance imaging uses radio frequency radiation as a source of energy while the subject is placed in a strong magnetic field. Figure

14 Positron Emissions Tomography (PET) Positron emissions tomography requires the administration (usually by I.V. line) of small amounts of organic molecules (commonly glucose) that have been labeled or "tagged" with a short life gamma ray emitting radioactive material. Active tissue areas, which take in more of the tracer, show up as brighter or "hot" spots and less active areas show up as dark or "cold" spots. Figure